Yellow sapphire and diamond ring

The cushion-shaped sapphire weighing 24.93 carats, flanked by 2 half-moon-shaped diamonds, mounted in 18 karat white gold, size 7. 

See GIA report stating the center stone is a natural sapphire, no heat. The sapphire is a slightly light shade of orangy-yellow and shows some color zoning, but is of a very nice clarity. The diamonds are approximately K-L color and VS-SI clarity. Heavy, well-made and in good condition.
In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective qualified opinion. Illustrations in the catalogue may not be actual size. Prospective purchasers are reminded that, unless the catalogue description specifically states that a stone is natural, we have assumed that some form of treatment may have been used and that such treatment may not be permanent. Our presale estimates reflect this assumption.
NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING CONDITION OF A LOT, ALL LOTS ARE OFFERED AND SOLD "AS IS" IN ACCORDANCE WITH THE CONDITIONS OF SALE PRINTED IN THE CATALOGUE.

Accompanied by GIA report no. 16160479 stating natural corundum, natural sapphire; no indications of heating.